The contributions of cortical areas to sensory, perceptual, motor and associative functions are studied in primitive mammals such as opossums, hedgehogs, tree shrews, and bush babies. Although strictly anatomical and electrophysiological techniques are often used, the research relies chiefly on ablation-behavior methods. Emphasis has been on auditory, visual, motor, temporal and prefrontal cortex and their associated behavior. BIBLIOGRAPHIC REFERENCES: Masterton, B., Thompson, G. C., Bechtold, J. K. & RoBards, M. J. Neuroanatomical basis of binaural phase-difference analysis for sound localization". Journal of Comparative and Physiological Psychology, 1975, 89, 379-386. Masterton, R. B. The method of compound stimuli for the assessment of cortical integration. In Prescott, Read and Coursin (Eds.), Brain function and malnutrition: Neuropsychological methods of assessment. Wiley & Sons, Inc. 1975.